Browsing by Author "Ho, Hsin-Hsin"

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Dithering skip modulator with a width controller for ultra-wride-load high-efficiency DC-DC converters
(2006-01-01)
Huang, Hong-Wei
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Ho, Hsin-Hsin
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Chien, Chieh-Ching
;
Chen, Ke-Horng
;
Ma, Gin-Kou
This paper proposes a temperature-independent load sensor to decide the optimum power MOSFET width for power saving of DC-DC converters. Besides, it also can decide the optimum modulation technique in tri-mode operation, which is composed of pulse-width modulation (PWM), pulse-frequency modulation (PFM), and a new proposed dithering sldp modulation (DSM). An efficiency-improving DSM operation is introduced to raise the efficiency drop because of transition from PWM to PFM. Importantly, DSM mode can dynamically sldp the number of gate driving pulses, which is inverse proportional to load current. Simplistically and qualitatively stated, the novel load sensor can automatically select the optimum modulation method and optimum power MOSFET width to achieve high efficiency over a wide load range. Experimental results show the tri-mode operation can have high efficiency about 89 % over a wide load current range from 3mA to 500mA. Owing to the effective mitigation of the switching loss contributed by large power MOSFET, the novel width controller not only achieves high efficiency about 95 % but also extends this high efficiency to a lower load current range about 0.1mA.
Dynamic droop scaling for improving current sharing performance in a system with multiple supplies
(2007-01-01)
Ho, Hsin-Hsin
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Chen, Ke-Horng
;
Chen, Wen-Tsao
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交大名義發表
;
National Chiao Tung University
A novel dynamic droop scaling (DDS) technique is proposed to improve current sharing performance of multiple supplies system. Owing to the implementation dual current sensing loops, the power dissipation of sensing resistor can be reduced compared with conventional droop technique. Besides, the dual current sensing loops not only increase droop slope but also eliminate the requirement of expensive and accurate external components. Furthermore, the proposed incremental output voltage circuit can raise output voltage to meet the requirement of allowable minimum output voltage according to increment of load current. It means that the DDS can break through the limitation of conventional droop technique. A system supplied by two supply modules with rated 20A output current demonstrates the correction of our DDS technique. The current difference between two supply modules can be shrunk from 12.5A to 2.9A. In other words, the error percentage of current sharing performance can be improved from 42.5% to 8.2%.
Dynamic droop scaling for improving current sharing performance in a system with multiple supplies
(2007-01-01)
Ho, Hsin-Hsin
;
Chen, Ke-Horng
;
Chen, Wen-Tsao
;
交大名義發表
;
National Chiao Tung University
A novel dynamic droop scaling (DDS) technique is proposed to improve current sharing performance of multiple supplies system. Owing to the implementation dual current sensing loops, the power dissipation of sensing resistor can be reduced compared with conventional droop technique. Besides, the dual current sensing loops not only increase droop slope but also eliminate the requirement of expensive and accurate external components. Furthermore, the proposed incremental output voltage circuit can raise output voltage to meet the requirement of allowable minimum output voltage according to increment of load current. It means that the DDS can break through the limitation of conventional droop technique. A system supplied by two supply modules with rated 20A output current demonstrates the correction of our DDS technique. The current difference between two supply modules can be shrunk from 12.5A to 2.9A. In other words, the error percentage of current sharing performance can be improved from 42.5% to 8.2%.
Fast transient DC-DC converter with on-chip compensated error amplifier
(2006)
Huang, Hong-Wei
;
Ho, Hsin-Hsin
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Chien, Chieh-Ching
;
Chen, Ke-Horng
;
Ma, Gin-Kou
A novel fast transient DC-DC converter with on-chip compensated error amplifier is presented in this paper. The error amplifier uses on-chip current-mode Miller capacitor to replace a large off-chip capacitor. Only three transistors and one voltage follower are used to implement this novel architecture. Not only on-chip compensated error amplifier is implemented without off-chip components and I/O pins, but also it can have fast transient response. Furthermore, we accurately decrease the transient response time without suffering from the oscillation issue. Experimental results demonstrate the stability and the fast transient response of the DC-DC converters.
High Efficiency and Smooth Transition Buck-Boost Converter for Extending Battery Life in Portable Devices
(2009)
Huang, Ping-Ching
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Wu, Wei-Quan
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Ho, Hsin-Hsin
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Chen, Ke-Homg
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電控工程研究所
This paper presents a high-efficiency and smooth-transition buck-boost (BB) converter to extend the battery life of portable devices. Owing to the usage of four switches, the BB control topology needs to minimize the switching and conduction losses at the same time. Therefore, over a wide input voltage range, the proposed BB converter consumes minimum switching loss like the basic operation of buck or boost converter. Besides, the conduction loss is reduced by means of the reduction of the inductor current level. Especially, the proposed BB converter offers good line/load regulation and thus provides a smooth and stable output voltage when the battery voltage decreases. Simulation results show that the output voltage drops is very small during the whole battery life time and the output transition is very smooth during the mode transition by the proposed BB control scheme.
High Efficiency Buck-Boost Converter with Reduced Average Inductor Current (RAIC) Technique
(2009)
Huang, Ping-Ching
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Wu, Wei-Quan
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Ho, Hsin-Hsin
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Chen, Ke-Horng
;
Ma, Gin-Kou
This paper presents a buck-boost converter with high-efficiency and smooth-transition to extend the battery life of portable devices. The new control topology minimizes the switching and conduction losses at the same time even four switches are used. Therefore, over a wide input voltage range, the proposed buck-boost converter with minimum switching loss like the buck or boost converter can reduce the conduction loss through the use of the reduced average inductor current (RAIC) level. Especially, the converter offers good line/load regulation and thus provides a smooth and stable output voltage without being affected by the decreasing battery voltage. Experimental results show that the output voltage is regulated for the whole battery life time and the output transition is very smooth during mode transition. Besides, the output voltage ripple and the average inductor current are effectively minimized by the proposed control scheme. The peak efficiency is 97% and output voltage ripple is reduced from 100mV to within 10mV.
Hybrid Buck-Boost Feedforward and Reduced Average Inductor Current Techniques in Fast Line Transient and High-Efficiency Buck-Boost Converter
(2010-03-01)
Huang, Ping-Ching
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Wu, Wei-Quan
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Ho, Hsin-Hsin
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Chen, Ke-Horng
;
電控工程研究所
This paper presents a buck-boost converter with high efficiency and small output ripple to extend the battery life of portable devices. Besides, the hybrid buck-boost feedforward (HBBFF) technique is integrated in this converter to achieve fast line response. The new control topology minimizes the switching and conduction losses at the same time even when four switches are used. Therefore, over a wide input voltage range, the proposed buck-boost converter with minimum switching loss like the buck or boost converter can reduce the conduction loss through the use of the reduced average inductor current (RAIC) technique. Moreover, the HBBFF technique minimizes the voltage variation at the output of error amplifier. Consequently, a fast line transient response can be achieved with small dropout voltage at the output. Especially, the converter can offer good line and load regulations to ensure a regulated output voltage without being affected by the decreasing battery voltage. Experimental results show that the output voltage is regulated over a wide battery lifetime, and the output ripple is minimized during mode transition. The peak efficiency is 97% and the transient dropout voltage can be improved substantially.
Improved current sharing performance by dynamic droop scaling technique in multiple power systems
(2007)
Ho, Hsin-Hsin
;
Chen, Ke-Horng
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a novel dynamic droop scaling (DDS) technique for paralleled power modules. The major concern is the uniform current distribution of each module in multiple power systems. The droop method relies on the slope characteristic of load regulation to achieve current sharing accuracy. Owing to the trade-off between error percentages of current sharing and output voltage variation, conventional droop technique can't provide good load regulation and current balance at the same time. However, the proposed DDS technique can break through the limitation of the conventional droop method by the implementation of dual current sensing loops. The dual current sensing loops not only increase the droop gain but also compensate the extra output dropout voltage automatically according to the steeper slope value of the novel method. Simulation results verify the error percentage of current sharing accuracy can be improved from 42.5% to 8.2% by DDS technique.
On-chip compensated error amplifier for fast transient DC-DC converters
(2006)
Huang, Hong-Wei
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Ho, Hsin-Hsin
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Chang, Chia-Jung
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Chen, Ke-Horng
;
Kuo, Sy-Yen
A novel on-chip compensated error amplifier for fast transient response of DC-DC converters is presented in this paper. The error amplifier uses on-chip current-mode Miller capacitor to replace a large off-chip capacitor. We only use three transistors and one voltage follower to implement this novel on-chip compensated error amplifier for fast transient DC-DC converters. Owing to the current-mode implementation, we can redirect the equivalent current to charge or discharge the output capacitor of the error amplifier to improve the transient response time. Not only on-chip compensated error amplifier is implemented without off-chip components and I/O pins, but also it can have fast transient response. The analytic equations guarantee the compensated correctness of the proposed circuit. With the proposed error amplifier, the transient response of DC-DC converters is improved significantly. Simulation results demonstrate the stability and the fast transient response of the DC-DC converters.
Optimum power-saving method for power MOSFET width of one-cycle control DGDC converters
(2006)
Chen, Ke-Horng
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Chien, Chieh-Ching
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Ho, Hsin-Hsin
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Huang, Li-Ren
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電控工程研究所
An optimum power MOSFET width technique is proposed in this paper for enhancing the efficiency characteristics of switching DC-DC converters. By implementing a one-cycle buck DC-DC converter, we demonstrate that the dynamic power MOSFET width controlling technique has much improvement in power reduction when the load current is light or heavy. The maximum efficiency of the buck converter is about 92% with 3% efficiency improvement for the heavy load condition. Besides, the efficiency can be enormously improved about 16% for light load condition as a result of the power reduction from the large power MOSFET transistors. Meanwhile, we also propose a new error correction loop circuit (ECL) to get a better load regulation than that of the previous designs. Furthermore, as compared to the adaptive gate driver voltage technique, the optimum power MOSFET width can achieve a great improvement on power saving. It is a better power-saving technique than the low-voltage-swing MOSFET gate drive technique for switching DC-DC converters.
Power-Tracking Embedded Buck-Boost Converter With Fast Dynamic Voltage Scaling for the SoC System
(2012-03-01)
Lee, Yu-Huei
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Huang, Shao-Chang
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Wang, Shih-Wei
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Wu, Wei-Chan
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Huang, Ping-Ching
A power-tracking embedded buck-boost converter with a fast dynamic voltage scaling (F-DVS) function is proposed to power the system-on-a-chip (SoC) system. To meet the power request of the SoC for different operation functions, fast up/down-tracking is implemented to achieve the F-DVS function. Recycling energy is also derived to minimize power dissipation during the down-tracking period. In addition, the peak current control and valley current control methods are utilized in the buck and boost operations, respectively, to minimize the effect of switching noise in high switching operation for compact solution. Moreover, the self-tuning pulse skipping mechanism extends the effective duty cycle to achieve voltage regulation and improves efficiency when the input voltage is close to that of the output. Through F-DVS, the tracking speed from 3 to 2 V and vice versa are 15 and 20 mu s, respectively, with a high switching frequency of 5 MHz.
Ratio Buck-Boost (RBB) Converter with Feed-Forward Technique for Achieving Fast Line Response
(2008)
Ho, Hsin-Hsin
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Huang, Pin-Chin
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Wu, Wei-Quan
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Chen, Ke-Horng
;
電控工程研究所
A ratio buck-boost (RBB) converter with feed-forward (FF) technique is proposed for regulating output voltage with fast line response. Owing to the ratio control technique, RBB converter can achieve high conversion efficiency due to only two turn-on switches within a switching period for all operation modes, which contains buck, boost, and buck-boost modes. Besides, feed-forward technique minimizes the voltage variations at the output of error amplifier. Thus, a fast line transient response can be achieved with small dropout voltage at the output. The proposed RBB converter with FF-technique is designed by TSMC 0.35um 2P4M process. Simulation results demonstrate the correction and performance of RBB converter with FF-technique. The transient dropout voltage can be decreased from 80mV to 3mV.
Slope control device capable of predicting uniform-current-sharing level and method thereof
(2009-09-03)
Ho, Hsin-Hsin
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Chen, Ke-Horng
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Hsieh, Chun-Yu
The present invention discloses a slope control device capable of predicting uniform-current-sharing level and method thereof which can be applied in a redundancy or distributed power system for providing better uniform-current-sharing ability. The device comprises a high linearity transconductor circuit, a slope adjusting circuit and an incremental output voltage circuit. The invention applies either a transductor parameter or a feedback resistor to increase the droop gain and therefore the current deviation between two power supply modules is reduced. The invention further raises the output voltage step by step to ensure that the output voltage meet the requirement of allowable minimum output voltage according to increment of load current.